There’s an old song comparing the wise man and the foolish man. It might just be talking about a tiny house foundation! Goes something like this: ‘the Foolish man built his house upon the sand … and the house came tumbling down. … The Wise man built his house upon a rock … and the house on the rock stood still.‘ – Or something like that. (If you know the words and the tune, ya gotta sing it!)
It’s an interesting metaphor that takes on a slightly different meaning when thinking about the foundation (trailer) for a Tiny House.
Yet, that’s what it is. You build a house on a foundation — and Tiny Houses are no different. The tiny house foundation IS the trailer, so it’s got to stand up to the environment — which includes not only the wind loads, snow loads, and regular wear and tear, but also rolling down the highway (over potholes, and other road debris).
Engineering Tiny House Trailers
At Synthesis, I get calls fairly frequently from people asking about trailers for a tiny house. The questions vary, of course, but the essence is often about “what can I get away with for a trailer?” Not so unlike sand, an insufficient trailer will not make a solid foundation, or stable platform to build your house on. Tiny houses definitely need a Specialty Trailer. And, we can learn a lot from the Old Time Tiny Houses with their unique mobile platform.
My Questions In Response To The Inquiries Are: How long do you want it to last? And, How much trouble do you want to deal with? The answers to these 2 questions (never asked directly) drive the trailer choice.
The Tiny House Trailer has to deal with a lot of different things that other trailers don’t, so the design must consider these conditions. You can read about the engineering and design process specifically for these Tiny House Trailers. The article explains so many of the considerations that go into creating the design. That’s the way we make decisions, and how we research things before diving in. You can read a similar discussion about the process in designing our Deck-Over style trailers.
That leaves only the matters of trailer size (to accommodate what kind of house), and what capacity (how much will the house weigh?). Weight we’ll discuss below, but size, that can be a Tiny House Quandary so we’ll leave that to you. We offer several sizes, including a couple that are extra wide if you need a little more space. Here’s some additional reading on Wide foundation trailers.
Tiny House Weight / Trailer Load Capacity
This is a tough one to grapple with. How much does a tiny house weigh? So many variables, and so much to consider. Does it have freshwater or black storage tanks? How many and what size of batteries? Appliances?
Compact is the reality and very nature of the tiny house, which means tighter and denser than a typical house. Also, being roadworthy requires an extra level of sturdiness. How much does that all weigh? Truly, it varies, and every house plan I’ve seen is unique, so you’ll need to do the math. However, from what we’ve seen, something in the neighborhood of 500# per linear foot is not out of the question. Some are more, some less – so don’t use this number and think you’re OK. Go back to the wise man song. The wise man also considers just how much rock he needs for the house to stand.
Take the weight information and it will point you to the right tiny house foundation. You’ll need one that exceeds whatever you calculate as the need. We recommend exceeding it by quite a bit since things always change and it’s so much better to over-design a bit, than to wish you had.
Side note, all the information, and the available Tiny House Trailer Plans are in Imperial dimensions. Read more about Metric here.
The New “Rock” To Build On
So, on that note, let’s introduce the new “Rock” and it’s big brother. Then, there’s the long one with a build choice of 30′ or 32′ deck length. Our latest DIY project is an amazing Tiny House Foundation – a trailer designed specifically for Tiny Houses. It’s designed to be really strong, easy to build, and to last (as the song says) … the Tiny House on the rock stands still.
These particular trailers are 100″ width (allowing for siding overlap and still be legal). DOT legal width limit is 8.5′ for the USA and Canada. Other countries are similar, but look it up. Our new tiny house foundations have 20′ or 24′ or 30′ or 32′ bed lengths. Other features include a max capacity of 14,000 lbs tandems (up to 18,000 lbs for the triple), and a low deck height with an integrated floor for even more headroom. As I speak to Tiny House creators, deck height is usually very high on the priority list, but there are trade-off’s. So, these new trailers not only have a low deck height, they also have the house floor integrated with the frame for better support and to minimize the true floor height.
Most important to this discussion, this Tiny House trailer minimizes deflection in all conditions even with the low deck height. This is key to longevity and stability of your home. See the discussion about deflection in our previous post. These trailer frames are very strong, yet more important, they’re stiff. So, if you build with care, it will make a very stable, very strong, Tiny House Foundation.
Compare this discussion on strength with some other popular opinions – though misguided – as in this YouTube Video review. Strength, yes. But stiffness is really the trailer limit for success with your tiny home.
It’s Your Turn – The Tiny House Foundation
If the foundation is the most important thing to get “right”, one of these new “Rocks” are a great choice. DIY plans are available for 3 versions our Tiny House Foundation (3 lengths). Select the size you want here. (Tiny House Foundation Trailers are down the page slightly.) Then, right after payment confirmation, you can save the blueprints directly to your computer. And, we take care of our customers, so let us know if you have trouble.
But, don’t think that these plans are the final work for your tiny house foundation. If your trailer design goals are not in perfect alignment with these plans, customize. We encourage customization — within certain limits.
We invite you to have a look at the plans, then let us know what you think.
Tiny House Foundation Update – 2021
We now have the Wide and the Extra Wide tiny house mobile foundations for you. From many requests, we are answering the needs our you, our customers. The 10′ wide by 32′ length is a fantastic size. Then, the really big (well, can we say “Large Tiny?” house) 12′ wide by 32′ length mobile foundation. (This size meets the max size recommendation guidelines as being a “tiny house” on wheels.) Both of these trailers will require permits to tow on the road, but if you want a little more elbow room in your tiny home, these wider foundations are certainly worth a look.
Update – 2023
By your request, we have added a few things and made a few changes to improve the 8.5′ x 32′ Tiny House Trailer Plans. Check out the list of improvements in the article “Next Generation Tiny House Trailer Design Improvements“. Some of these changes are specific to this trailer. Others will cascade across our whole line of tiny house foundation plans as we get time to do all the needed engineering analysis.